Environmental Entomology最新文献

The increase in extreme climate events in recent years has been considered as an important factor affecting forest pests. Understanding the responses of forest pests to climate is helpful for revealing the trends in forest pest dynamics and proposing effective control measures. In this study, the relationship between the dynamics of all forest pests, independent forest diseases, and forest insect pests with the climate was evaluated in China, and the corresponding differences among forest pests, diseases and insect pests were assessed. Based on cross-wavelet transform and wavelet coherence analysis, the influences of teleconnection factors on the relationship between climate and forest pests were quantitatively analyzed to determine the roles of these factors. The results indicate that (i) three types of disasters in most parts of China have decreased from 1979 to 2019, while forest pests and forest insect pests in the southwestern region have increased; (ii) the relationship among Forest Pest Occurrence Area Rate and climate factors such as the Multivariate ENSO index, Southern Oscillation index, Arctic Oscillation (AO), Atlantic Multidecadal Oscillation (AMO), and Sunspot is more significant; (iii) the cycle is short in most regions, with oscillations in 2-4 years bands being the main variation periods of disasters in East, Central, and South China; (iv) There is a significant correlation between climate and disasters in the periods of 2-4 or 8-10 years. The AO, AMO, and Sunspot were important driving factors affecting the relationship between climate and disasters. Specifically, the Sunspot had the greatest impact among these factors.

Atmospheric and soil nitrogen levels are increasing across the world. Nitrogen addition can alter vegetative and flower traits, including flowering phenology, floral production, and flower morphology, and the quantity and quality of floral rewards such as nectar. However, it is not well understood if and how these changes in floral traits will affect foraging preferences and pollination by different pollinator species. We hypothesized that honey bees (Apis mellifera) would exhibit a preference for plants with increased numbers of flowers, while bumble bees (Bombus spp.) would exhibit a preference for plants with increased nectar production as a result of soil nitrogen addition. A 2-yr field experiment was conducted to investigate the effects of varying nitrogen supply levels (e.g., 0, 4, 8 kg N ha-1 yr-1 of N0, N4, and N8) on the vegetative and floral traits of a perennial plant (Saussurea nigrescens), as well as the visitation rates of introduced managed honey bees (A. mellifera) and the native wild bumble bees. The results showed that adding nitrogen increased the number of flowers and nectar production. However, honey bees and bumble bees were responding to different floral resources that induced by nitrogen addition, with honey bees prioritizing the number of flowers and bumble bees prioritizing nectar quantity. The findings shed new light on how plants and pollinators interact when nitrogen is added, as well as how pollinator communities will be affected in the future.

Red maples (Acer rubrum L.; Sapindales: Sapindaceae) are common shade trees well known for their stunning autumn foliage and fast growth. They are a popular choice for landscapes, parks, and public places across the United States. Flatheaded borer species in the genus Chrysobothris (Coleoptera: Buprestidae) are some of the most damaging insects in red maple production, with attacks being most common on stressed and newly transplanted trees. In nurseries, red maples routinely experience flatheaded borer attacks, while the Freeman maple hybrid 'Autumn Blaze' has been reported as potentially resistant to flatheaded borers. In this study, traits of three borer susceptible red maple cultivars ('Brandywine', 'Sun Valley', and 'October Glory') were compared against a potentially resistant Freeman maple hybrid cultivar for baseline differences as well as differences under the stress of a foliar herbicide application Scythe (pelargonic acid 57%). Morphological, physiological, and biochemical traits of the red maple cultivars were evaluated and contrasted with the hybrid to identify traits related with borer resistance. Under normal conditions, the hybrid maple exhibited faster growth, greater concentrations of sulfur, and lower concentrations of zinc and flavonoids in leaf tissues compared to red maples. The herbicide stress treatment resulted in greater nitrogen and sulfur concentrations in hybrid foliage, but less chlorophyll, flavonoid, and zinc concentrations compared to the red maple cultivars. Field trials validated borer preference for red maples over the hybrid. Traits associated with the hybrid warrant additional study if an understanding of the causal relationship with borer resistance is to be achieved.

We describe experiments that evaluated potential sex pheromone components for 6 North American click beetle species. In field trials in Illinois, South Carolina, North Carolina, and Virginia, male beetles of 6 species were strongly attracted to geranyl butyrate (Agriotes insanus Candèze), 5-methylhexyl (Z)-4-decenoate (Elater abruptus Say), 11-dodecenyl butyrate (Melanotus ignobilis Melsheimer), and limoniic acid (Gambrinus griseus [Palisot de Beauvois], G. rudis [Brown], and G. plebejus [Say]). Collection of E. abruptus in South Carolina represents a new state record. For each species, capture rates varied geographically and temporally, possibly due to differences in local population densities and regional phenology, or the efficiency of different trap designs or trap placement. Structural similarities were observed between the tested attractants and previously identified pheromones of closely related species. For example, males of A. insanus were attracted to geranyl butyrate, analogous to the terpenoid ester pheromones of a number of European congeners. The attractant for E. abruptus, 5-methylhexyl (Z)-4-decenoate, is an analog of the pheromone of its European congener E. ferrugineus L., and the attractant for M. ignobilis, 11-dodecenyl butyrate, is an analog of attractants of European and Asian congeners. Attraction of the 3 Gambrinus species to limoniic acid parallels recent reports of attraction of the congeners G. seminudus (Van Dyke) and G. ursinus (Van Dyke) to this compound, which was originally identified from closely related species of Limonius. Full identifications of additional sex pheromones for elaterid species should provide a more complete picture of the diversities/similarities of the semiochemicals mediating reproductive behaviors of this biologically diverse and taxonomically complex group.

Anoplophora glabripennis (Motschulsky), the Asian longhorned beetle, is a serious wood-boring pest of hardwood trees. There have been records that suggest Elaeagnus angustifolia L. (Elaeagnaceae) might be an "attract and kill" tree species for A. glabripennis, i.e., a tree that is attractive to A. glabripennis adults but kills their oviposited eggs. To evaluate the possibility of E. angustifolia as a control measure for A. glabripennis, we carried out a series of behavioral experiments in the laboratory and in the field. Results showed that: (i) A. glabripennis females preferred E. angustifolia branches and leaves over poplar tree species evaluated; the weight of feces from both female and male A. glabripennis feeding on E. angustifolia was significantly higher than from those feeding on Populus deltoides 'Shalinyang' or Populus alba. L. var. pyramidalis; (ii) the average lifespan of females and males feeding on E. angustifolia was significantly longer than those feeding on other host trees evaluated; (iii) in the laboratory oviposition choice experiment, there were significantly fewer egg notch grooves on E. angustifolia than on P. deltoides 'Shalinyang', and those made in E. angustifolia were without eggs; (iv) in the field, the number of egg notch grooves on E. angustifolia was 43.6 ± 18.1 per stem, but the number of eggs laid was only 14.4 ± 6.4 per stem; and (v) Field surveys of existing mixed forests showed that when E. angustifolia was planted with P. alba. var. pyramidalis or Populus simonii × (Populus pyramidalis + Salix matsudana) 'Poparis' in the mixed forest, both poplar varieties suffered greater infestation than E. angustifolia. Therefore, E. angustifolia is not a suitable attract and kill tree to be extensively planted in mixed forests for control of A. glabripennis.

Neonicotinoid insecticide seed treatments are commonly used in rice (Oryza sativa) production to control rice water weevil (Lisorhoptrus oryzophilus). With the use of neonicotinoid seed treatments, there is potential that honey bees (Apis mellifera) could be exposed to neonicotinoids through translocation to the pollen. Studies were conducted in 2015 and 2016 to determine the level of neonicotinoids present in flag leaves, pollen, and grain of rice. Thiamethoxam was applied as a seed treatment and foliar prior to flooding. Clothianidin was applied as a seed treatment and as a foliar at a preflood and postflood timing. Subsamples of flag leaves, pollen, and grain were analyzed for positive neonicotinoid detections and abundance. Thiamethoxam was detected in 8.9% of samples and clothianidin was detected in 1.4% of samples. For both thiamethoxam and clothianidin, more positive samples were observed in flag leaf samples than in pollen or grain. An average of 4.30 ng/g of thiamethoxam was detected in flag leaves from seed-applied thiamethoxam. An average of 1.25 ng/g of clothianidin was found in flag leaves from a preflood application of clothianidin. A survey of honey bees present in rice fields was conducted in Mississippi and Arkansas to determine the abundance of honey bees present in rice fields based on the time of day. Honey bee densities were low in rice, with less than 5% and 3% positive detections observed in Mississippi and Arkansas, respectively. More positive detections and higher densities of honey bees were observed for mid-day sampling than for morning or evening sampling.

Domestication can lead to significant changes in the growth and behavior of organisms. While the threat of predation is a strong selective force in the wild, the relaxation or removal of this threat in captive-rearing environments selects for reduced sensitivity to biotic stressors. Previous work has documented such changes in other taxa, but no work has been done on domestication-related losses of predation risk sensitivity in insects. We exposed both wild and domesticated (>50 generations in captivity) Lymantria dispar dispar (Lepidoptera: Erebidae) larvae to recordings of predators (wasp buzzing), nonpredators (mosquito buzzing), or no sound to compare the effects of predation risk on the two stocks. Wasp buzzing, but not mosquito buzzing, decreased survival of wild caterpillars relative to the control; domesticated caterpillars showed no such response. Domesticated L. dispar larvae appear to have reduced sensitivity to predation risk cues, suggesting that captive-reared insects may not always be analogs to their wild counterparts for risk-related behavioral studies.

Apis mellifera Linnaeus (Hymenoptera: Apis), honey bees, are the most widely used managed crop pollinators. However, their high rental cost and uncertain availability for North American orchard crops have motivated growers to explore alternative pollination options. We examined whether adding solitary, spring-flying Osmia lignaria Say (Hymenoptera: Megachilidae), blue orchard bees, as co-pollinators with A. mellifera in Washington sweet cherry and pear orchards enhances fruit set and yield compared to the use of A. mellifera alone. We added managed O. lignaria to orchard sites where A. mellifera hives were already present. Fruit set, fruit yield, and O. lignaria reproduction at O. lignaria-supplemented sites were compared to nearby, paired sites pollinated only by A. mellifera (3 paired cherry and 3 paired pear sites). For both crops, the addition of O. lignaria significantly increased fruit set but did not yield at harvest. Microscopic inspection of pollen grains from O. lignaria nest cell provisions confirmed that O. lignaria primarily visited orchard flowers. Mean retention of O. lignaria in cherry orchards was slightly higher (65%) than O. lignaria retention reported in other orchard crops (30%-60%). However, retention in pear orchards was much lower (≤20%). These results show that supplementing hives with O. lignaria in Washington spring orchard crops can increase overall pollination, but that trees fail to bear developing fruit to maturity. The strategy of using co-pollinators, O. lignaria and A. mellifera, in US orchards may act as "pollination insurance" when A. mellifera hives are in low supply or when the weather is not amenable for A. mellifera flight during the bloom period.

Ensuring the safety of insecticides to natural enemy insects of pests is crucial for integrating chemical and biological control strategies. Broflanilide, a novel meta-diamide insecticide, exhibits high insecticidal activity against Myzus persicae (Sulzer) (Hemiptera: Aphididae). To integrate chemical and biological control against M. persicae, we assessed the toxicity of broflanilide to Aphidius gifuensis, and evaluated its safety and sublethal effects. The LC10, LC25, and LC50 values of broflanilide against A. gifuensis were 0.733 mg/L, 1.613 mg/L, and 3.852 mg/L, respectively. The selectivity toxicity ratio of broflanilide to A. gifuensis was 1.516, indicating higher toxicity to M. persicae compared to A. gifuensis. The risk quotient of broflanilide to A. gifuensis adults was 6.18. The percent reduction in the emergence of the parasitoid pupae was -1.15, with a risk grade of 1. The sublethal concentration of broflanilide had no significant influence on the intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), and mean fecundity (F) of A. gifuensis in the F1 generation. The mean generation time (T) increased by 0.51 days and 0.39 days in the LC10 and LC25 treatments, respectively; the difference between LC10 treatment and the control was significant, while the difference between LC25 treatment and the control was not significant. The results showed that the sublethal concentration of broflanilide did not have a significant inhibitory effect on the population growth of A. gifuensis.

Microplastics (MPs) and nanoplastics (NPs) are pervasive environmental pollutants that are commonly ingested by organisms at different trophic levels. While the effects of MPs on aquatic organisms have been extensively studied, the impacts of MP ingestion on the host fitness of terrestrial organisms, mainly insects, have been relatively unexplored. This study investigates the effects of MP and NP ingestion on the survivorship and reproduction of 2 medically important mosquito species, Aedes aegypti Linnaeus (Diptera: Culicidae) and Aedes albopictus Skuse (Diptera: Culicidae). Larval and pupal survivorship of Ae. albopictus were not significantly affected by particle size or concentration, but there was a reduction of Ae. aegypti pupal survivorship associated with the ingestion of 0.03 µm NPs. In addition, there was little observed impact of 0.03 µm NP and 1.0 µm MP ingestion on adult survivorship, fecundity, and longevity. To further investigate the effects of MP ingestion on mosquito fitness, we also examined the effects of MPs of varying shape, size, and plastic polymer type on Ae. aegypti immature and adult survivorship. The data suggest that the polymer type and shape did not impact Ae. aegypti immature or adult survivorship. These findings highlight that understanding the effects of microplastic ingestion by mosquitoes may be complicated by the size, composition, and amount ingested.